Route 1

You can access Route 1 directly from the north of Pallet Town. Since you don't own any Poké Balls yet, there's not much you can do here except for battling Rattata and Pidgey. Note that you only get attacked when you walk through the tall grass. So if you're low on HP and you're trying to avoid fights, stay on the path. Remember to always talk to the people you meet -- otherwise you could miss out on valuable items (such as the Potion you get from the first guy you bump into).

This is also the first time you see the small ledges that run horizontally through the landscape. You can only jump down these ledges from the top to the bottom. They will block your way when you're trying to go the other way.